proxmark3/armsrc/hfsnoop.c

#include "proxmark3.h"
#include "apps.h"
#include "BigBuf.h"
#include "util.h"
#include "usb_cdc.h" // for usb_poll_validate_length

static void RAMFUNC optimizedSniff(void);

static void RAMFUNC optimizedSniff(void) {
    int n = BigBuf_max_traceLen() / sizeof(uint16_t); // take all memory

    uint16_t *dest = (uint16_t *)BigBuf_get_addr();
    uint16_t *destend = dest + n - 1;

    // Reading data loop
    while (dest <= destend) {
        if (AT91C_BASE_SSC->SSC_SR & AT91C_SSC_RXRDY) {
            *dest = (uint16_t)(AT91C_BASE_SSC->SSC_RHR);
            dest++;
        }
    }
    //setting tracelen - important!  it was set by buffer overflow before
    set_tracelen(BigBuf_max_traceLen());
}

void HfSniff(int samplesToSkip, int triggersToSkip) {
    BigBuf_free();
    BigBuf_Clear();

    Dbprintf("Skipping first %d sample pairs, Skipping %d triggers.\n", samplesToSkip, triggersToSkip);
    int trigger_cnt = 0;

    LED_D_ON();

    FpgaDownloadAndGo(FPGA_BITSTREAM_HF);

    SetAdcMuxFor(GPIO_MUXSEL_HIPKD);

    // Set up the synchronous serial port
    FpgaSetupSsc();

    // Setting Frame Mode For better performance on high speed data transfer.
    AT91C_BASE_SSC->SSC_RFMR = SSC_FRAME_MODE_BITS_IN_WORD(16);

    FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_SNOOP);
    SpinDelay(100);

    uint16_t r = 0;
    while (!BUTTON_PRESS() && !usb_poll_validate_length()) {
        WDT_HIT();

        if (AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_RXRDY)) {
            r = (uint16_t)AT91C_BASE_SSC->SSC_RHR;
            r = MAX(r & 0xff, r >> 8);
            if (r >= 180) {  // 0xB4 ??
                if (++trigger_cnt > triggersToSkip)
                    break;
            }
        }
    }

    if (!BUTTON_PRESS()) {
        int waitcount = samplesToSkip; // lets wait 40000 ticks of pck0
        while (waitcount != 0) {

            if (AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_RXRDY))
                waitcount--;
        }
        optimizedSniff();
        Dbprintf("Trigger kicked! Value: %d, Dumping Samples Hispeed now.", r);
    }

    //Resetting Frame mode (First set in fpgaloader.c)
    AT91C_BASE_SSC->SSC_RFMR = SSC_FRAME_MODE_BITS_IN_WORD(8) | AT91C_SSC_MSBF | SSC_FRAME_MODE_WORDS_PER_TRANSFER(0);

    DbpString("HF Sniffing end");
    FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
    LED_D_OFF();
}